1. Field of the Invention
Our invention relates to spray nozzles which are nonplugging and/or self-cleaning.
2. Description of the Prior Art
The prior nozzle art teaches it is old to provide a set of holes around an inner tube. In the U.S. Pat. No. 3,460,764 (Wallis) such an arrangement is disclosed in which air is supplied to the holes to control divergence of the coating particles from the inner tube and to produce a protective air stream. The U.S. Pat. Nos. 3,364,970 and 3,484,044 (both to Dombruch et al) show a center oxygen stream with a high velocity which induces the gas in an intermediate stream to flow towards the outer periphery of the center stream. Other United States patents of interest include U.S. Pat. Nos. 743,777 (Tucker et al), 1,991,894 (Forney), and 2,881,826 (Spies).
What the known prior art does not disclose is a simple and effective selfcleaning non-plugging spray nozzle having an inner nozzle conduit with an externally mounted fluid ring having holes therein, wherein a narrow space between the ring mount and the inner nozzle conduit induces an air flow to clean the nozzle.
The invention described herein was disclosed in the United States Bureau of Mines Report of Investigation (RI) 8266 entitled "Dry-Process Sprayed Coal Mine Sealants, An Updated Progress Report" first published in Nov. 17, 1977 and authored by Jack E. Fraley. The contents of this report are specifically incorporated by reference herein.